Many types of tomatoes, especially those intended for table consumption are picked from standing or supported vines which in turn support the tomatoes well above the ground. The harvested crop when it is harvested in the field is quite clean and well selected because when picked it is above the ground and clean, and carries with the tomato only a desired part of the stem, without dirt. These tomatoes are generally carefully handled, and arrive from the field clean and attractive.
There is another class of tomato that is grown principally to be processed, generally into a fluid product such as tomato paste, puree, or juice. These processor tomatoes are not intended to be served on the table as such. Their shape and structure in the sense of attractiveness to a diner or retail customer are of no importance. Instead they ultimately are processed into fluid products such as ketchup, tomato paste and dressings. The ultimate consumer will never see the original tomato, and probably never any one just like it.
It is not surprising that growing plants have been developed which produce tomatoes having a skin hardy enough to withstand mechanical picking and handling. One type, with which this invention is not concerned, grows to a height at which a mechanical harvester can pick the tomatoes from a standing vine as it passes along a row. This is a useful type, and can produce tomatoes which will be attractive to the diner. They are produced at the cost of trellissing and careful handling.
Another type, with which this invention is concerned, is more economical in the planting and growth of the vines, and which requires minimal attention during its growing season. Such vines, when growing their crop, first grow upwardly to a small height, and then droop over and down toward the ground, suspending the tomatoes within the vine structure. The vine actually covers and shrouds the tomatoes rather in a mound shape. These vines are planted as individual plants in rows, and are intended for least maintenance and harvest costs.
Such crops are grown in very large fields, often numbering in the hundreds of acres for one planting. Accordingly, large harvesters are needed and are used to harvest such crops. They grasp and pull the vine up out of the ground, sometimes severing the root (leaving it behind), and while suspending it shake the vine vigorously to release the tomatoes. The vine is left behind in the field, later to be plowed under, while the product of the shaking procedure is a “gathering” deposited on an elevator which carries it as a raw stream into the harvester for collection of the tomatoes.
Here the problems begin. A simple problem is the separation of green tomatoes from red tomatoes. This is regularly done by a color-responsive discriminator that divides the tomatoes into two streams—the red and the green. The color of the tomato has a particular relation to the usefulness of the tomato for specific ultimate products. Properties such as viscosity vary with the ripeness and color of the tomato.
A major problem is that the lifting of the vine to release the tomatoes also carries along some roots, branches, twigs, dirt, and dirt clods, collectively referred to herein as debris and detritus. When the vine is shaken over the elevator, some of this will accompany the tomatoes into the system. Also, some of the tomatoes will be heavily covered with dirt, which affects their perceived color.
In order ultimately to produce a processed product of suitable quality, the debris and detritus must be removed before the tomato part of the gathering can be accepted into the subsequent processing of the tomato into the fluid product. Of course this clarification of product can all be done later in the processing plant with the use of labor and much water, but it is costly, and the purchase price paid for the submitted product is reduced by the cost of the clarification. The task at hand is to reduce the need for clarifying the material to be delivered to the processor by doing as much of it as possible while the crop is still in the field, and in particular before it reaches the processing plant, which will surcharge a load for the trash it brings.
Some efforts are routinely made in the field for this purpose, and have been for a long time. Commercial harvesters are very large vehicles with carrying capacity for substantial accessory machinery and personnel. At the present time, when the initial stream exits the discriminator, it is dumped toward another moving conveyor belt. Tomatoes of a color to be rejected, perhaps green, are diverted, and the remainder flies to the belt. At this juncture some of the debris and detritus will fall away into the gap between these belts. Immediately downstream, one or two people stand alongside this belt and manually remove the debris and detritus which accompanies the tomatoes past the first discriminator and the gap. They also remove tomatoes of questionable or borderline quality which were incorrectly passed by the first discriminator.
This next manual function is very costly, but is affordable with present wage and cost schedules. In one major field operation, the cost of this manual function is about $1,200,000,00 per year. The use of this invention is expected to reduce this cost to less than $250,000,00 with equal or better results.
Besides being costly, the persons involved are themselves a limitation on the speed of the harvester. To speed the process beyond their capacity is not possible, because the incoming stream would only back up or undesirable product would be passed. The harvester itself must slow down to their rate.
Even more to the point, these persons are working in a noisy, dusty and hot environment, exercising selective judgement about what is to be left on the belt or removed from it. While the selection appears at first to be simplistic, it is not so simple after all. There must be a cognitive recognition of many shapes, sizes, colors and textures. Ultimately fatigue sets in and performance will be degraded.
The degradation can take many forms. The recognition of material to be rejected when viewed by a person involves neurological processes that unconsciously respond to various conditions of dirt, color, size, texture, and quality (freshness and broken product, for example). A very tired person can be expected to be less responsive to these, so that the results will vary from time to time for a given person, and also from person to person.
In contrast, a mechanical and electronic discriminator can be “set” to specific parameters, and it does not tire or vary in its response. This is not merely the substitution of a mechanical or optical device for the human responses. The substitution of a person by a sensor accomplishes more than the absence of fatigue or reduction of payroll. This invention, properly applied, results not only in a cleaner product with more value at the processor, but does so with a uniformity not attainable from the performance of a group of individuals. The ultimate performance is significantly improved, as evidenced by the cash value of the product.
It is an object of this invention to remove debris and detritus from a stream of freshly harvested processor type tomatoes at the harvester while in the field, and to produce a stream with greater cash value at the processing plant because the processing plant pays for the tomatoes on the basis of net useful product, taking into account the expense of cleaning up the product stream. Accordingly this invention significantly improves the cash value of the crop while producing a crop that requires less environmentally troublesome clarifying procedures.